In a typical manner, technological progress in the manufacturing of complementary metal-oxide semiconductor (CMOS) transistors, with ever smaller dimensions and thickness of the corresponding oxides, has led to a progressive reduction in the supply voltages used in the corresponding electronic circuits (in order not to cause damage thereto), for example, down to values in the range of 1 V-1.1 V. However, there is frequently the need to have available voltages different from the supply voltage, in particular a higher value. For this purpose, charge pumps are usually used, possibly combined with voltage regulators, in particular, direct current-direct current (DC/DC) converters, which may need to meet stringent requirements from the standpoint of electrical performance in order not to jeopardize the general performance of the electronic circuits in which they are used.
For example, in nonvolatile memories, in particular of a flash type, operations of reading and programming, or modification, require high operating voltages for the terminals of the memory cells, for example, in the range of 5 V for the reading operations and 10 V for the programming operations. For generation of such operating voltages, charge-pump circuits are used, which, at their input, may require regulated voltages of a value generally higher than the voltage supplied by the supply source, for example, in the range of 1.4 V, for generation of which suitably configured voltage regulators are used.
The electrical performance of these voltage regulators, for example, in terms of static and dynamic consumption levels, output impedance, occupation of area, and stability margins, may be critical, for example, on account of the inefficiency typical of the associated charge pumps. There are also applications entailing stringent safety requirements, for example, in the case of the so-called “Secure MCUs”, i.e., microprocessor units for secure applications, for example, banking applications, computer security, payments, etc.